A swimming pool, also known as a bathing or wading pool, is a structure that holds water for swimming or other aquatic activities. It can be built into the ground (in-ground pool), or above ground (as a freestanding construction or as part of a building or other larger structure). Pools may follow standardized sizes, including Olympic size, or be custom in shape. They may be indoor or outdoor, and public or private. They may be used for competition or recreational swimming, or for training swimmers. They can be a feature of an amusement park or waterpark, or as a part of a health club or fitness center. Many hotels have pools for their guests, and they are also commonly found in holiday resorts and in tourist areas. Many apartments and residential neighborhoods have pools as well, and they are often used for recreational and exercise purposes.
Swimming pools are used for a variety of water-based recreational activities, and they may be adapted with water slides, fountains, underwater lighting, whirlpool tubs, sand beaches, and other features. Swimming is a low-impact activity that can improve muscle strength, balance and flexibility, and increase endurance. It can help prevent or reduce the symptoms of arthritis and back pain, and it may be helpful for people with cardiovascular disease.
Drowning is a risk for people using pools, particularly young children, and swimming pools are sometimes the scene of fatal accidents. In some countries, residential pools must be fenced and supervised, and safety precautions include the use of lifeguards and barriers to prevent unauthorized access.